1. Field of the Invention
This invention relates to a new method and engines for converting caloric energy into work, making practical a thermodynamic cycle heretofore thought ideal, or only theoretical. More particularly, this invention relates to a new method having a plurality of embodiments for doing work in which substantially all or only a portion of the theoretical available energy can be used in accordance with a newly pragmatic thermodynamic cycle, depending upon the operating conditions in which the new method is to be employed.
2. Description of the Prior Art
The prior art has seen the development of a wide variety of methods and heat engines creating a variety of thermodynamic cycles. These have ranged from the internal combustion engines with the Otto cycle and the diesel cycle through the externally fired heat engines, with the Rankine cycle and the Stirling cycle.
One trouble with a prior practical Stirling cycle prime mover is that the heat engine is simultaneously a refrigeration machine covertly draining heat source energy at the expense of the prime mover phenomenon taking place. This happens because the prime mover direction of rotation is the same direction which by notorious heat pump effect would cause the engine hot end temperature to drop below ambient, for illustration, if that machine were purposely overdriven. The net result is more heat being drained from source and rejected to sink than might otherwise be expected.
Another trouble with many "external combustion" engines is the use of regenerators/recouperators. The object is to "recoup" the heat lost in high temperature exhaust gas by using it to heat newly compressed working fluid. The trouble is that this effect cuts off when exhaust temperature drops to compressor outlet temperature. Such devices invariably reject the heat of compression. When one is used there is no possible way to avoid this undesirable effect. It can only be minimized by other deleterious compromise such as lowered compression ratio plus pressurization or increased displacement. But compression ratio cannot be reduced to zero because at zero pressure difference no work can be rendered. At best the regenerator exhaust temperature will be significantly higher than some other more ideal means of obtaining low exhaust temperature. Thus many good sources of heat are not hot enough to energize existing engines. Thus in response to the workings of supply and demand the costs of energy are higher than they might otherwise be.
One of the best theoretical cycles is the Carnot cycle which is the theoretical cycle of an ideal heat engine of maximum thermal efficiency. This has been the ideal toward which others approach but has not been realizable because no practical way has yet been developed to achieve the results of isothermal expansion, isentropic expansion, isothermal compression, and isentropic compression to the initial state.